Labels are used on optical media, such as compact discs (CDs) and digital versatile discs (DVDs), typically to provide human-readable indicia of data content recorded on the media, artwork, and the like. Such labels may be prepared on a separate medium such as adhesive-backed paper suitable for affixing to an optical disc, or may be marked directly upon a surface of the optical medium.
Screen printing methods have conventionally been used to label surfaces of optical discs; however, preparation of a stencil for screen printing is an elaborate, time-consuming and expensive process, rendering the method cost-ineffective for labeling single discs or a relatively small number of discs.
Conventional printer mechanisms, such as off-the-shelf inkjet printers, are typically optimized for sheets of paper and are typically based on Cartesian coordinates, producing lines, strips, or rectangles of coverage. Special-purpose printers, incorporating a tray for holding a CD/DVD, may use conventional inkjet technology to print directly on the label side of an optical disc, but such printers are fairly expensive and bulky.
In a conventional CD/DVD drive, a motor rotates an optical disc relative to a conventional optical marking mechanism, such as a laser. Recent advances allow a laser to also be used as the marking mechanism, where labeling or marking is accomplished by generating a beam for optically marking a surface of the medium. When a conventional marking mechanism is used to mark a plurality of concentric circular tracks on an optical disc, such as a CD or DVD, a length of time is needed to reposition and stabilize the marking mechanism when advancing between tracks. Meanwhile, the disc may be constantly rotating. Conventionally, starting positions for each track are aligned together on a radial line. However, by the time the marking mechanism has completed marking all the pixels of a track and has advanced to a next track and become stabilized, the disc will have rotated past the next starting position. Before writing can commence at the next starting position, a waiting period will be required for the disc to complete a revolution, such that the mechanism is positioned at the starting position for the next track. This waiting period increases the overall time required for the marking mechanism to write a complete set of track data.